1. Field of the Invention
The present invention relates to a microdevice. More particularly, it relates to a microdevice which manufactures materials and products by mixing or reaction of fluids in the fields of chemical industry and pharmaceutical industry, and specifically in which a plurality of fluids are caused to pass through respective fluid supply passages and flow together in one mixing reaction flow path, and the fluids are diffused in the normal direction of the contact interface thereof while being allowed to flow as a thin layer shaped laminar flow, by which mixing or reaction is carried out.
2. Description of the Related Art
Recently, in the chemical industry or the pharmaceutical industry relating to the manufacture of medicines, reagents, etc., a new manufacturing process using a minute vessel called a micromixer or a microreactor has been developed. The micromixer or the microreactor is provided with a minute space (mixing reaction flow path) which connects with a plurality of fine fluid supply passages and has a circle equivalent diameter (an equivalent diameter in the case where the cross section of the minute space is converted into a circle) of about several micrometers to several hundred micrometers. By this configuration, a plurality of fluids passing through the fluid supply passages are allowed to flow together in the minute space to mix the fluids or to subject the fluids to chemical reaction while mixing. The micromixer and the microreactor have a common basic construction. In some cases, a device in which the fluids are mixed is called a micromixer, and a device in which the fluids are subjected to chemical reaction when they are mixed is called a microreactor. In the present invention, a device having a minute space usable as the micromixer and the microreactor is called a microdevice.
Such microdevices have been disclosed, for example, in PCT International Unexamined Patent Publication No. WO 00/62913, National Publication of International Patent Application No. 2003-502144, and Japanese Patent Application Publication No. 2002-282682. Any of these microdevices is configured so that two kinds of fluids are caused to pass through respective fine fluid supply passages and are introduced into a minute space as a very thin layer shaped laminar flow, by which two kinds of fluids are mixed and allowed to react with each other in the minute space.
Next, explanation will be given of points where the mixing and reaction accomplished by the above-described microdevice differ from the batch mixing and reaction using a stirring tank etc. Since chemical reaction generally takes place due to meeting of molecules at an interface of reaction fluids, if the reaction is carried out in a minute space, the interface area increases relatively, so that the reaction efficiency increases remarkably. Also, for the diffusion itself of molecules, the diffusion time is proportional to the square of distance. This means that even if the reaction fluids are not mixed positively as the size of minute space is decreased, the mixing proceeds due to the diffusion of molecules, and the reaction takes place easily. Also, in a minute space, a flow in which laminar flow is dominant is provided because the size is small, and the fluids are diffused in the direction perpendicular to the flow while flowing in a laminar flow state, by which mixing or reaction is carried out.
By using such a microdevice, the mixing time, reaction time, mixing temperature, and reaction temperature of fluids can be controlled with high accuracy, for example, as compared with the conventional batch system using a large-volume tank etc. as a place for mixing or reaction. Also, in the case of the batch system, especially for fluids whose reaction time is short, reaction proceeds on the reaction contact surface at the early stage of mixing, and further a primary product yielded by the reaction of fluids is successively subjected to reaction in the tank, so that there is a fear that a inhomogeneous reaction product is yielded. On the other hand, in the case of the microdevice, the fluid flows continuously without staying in the minute space, so that a primary product yielded by the reaction of fluids is not successively subjected to reaction in the minute space. Therefore, a pure primary product, which has been difficult to take out conventionally, can be taken out.
Also, when a small quantity of a chemical substance manufactured by experimental manufacturing equipment is manufactured in high volume by large-scale manufacturing equipment, conventionally, much labor and time have been required to obtain reproducibility of the experimental manufacturing equipment in the large-scale batch manufacturing equipment. However, by a numbering-up idea in which manufacturing lines using a microdevice are arranged in parallel according to the production quantity, the labor and time for obtaining such reproducibility may be decreased significantly.
However, the microdevice requires a very narrow fluid supply passage of about several micrometers to several hundred micrometers. Therefore, in manufacturing the microdevice, a special precision microfabrication technique such as photolithoetching, electrical discharge machining technique, and optical molding method is required, so that not only the manufacturing period of time is long but also the manufacturing cost is high.
However, if an attempt is made to manufacture a microdevice without using the special precision microfabrication technique, the opening width of fluid supply passage capable of being manufactured is limited, so that the thicknesses of fluids flowing together in the mixing reaction flow path, which is a minute space, through a plurality of fluid supply passages increase. Thereby, the diffusion time for diffusing the fluids in the normal direction of the contact interface of fluids is made long, which presents a problem in that rapid and homogeneous mixing or reaction, which is a feature of microdevice, cannot be carried out.